The present invention relates to an analog liquid crystal display apparatus. It is employed in the field of electrooptics, particularly in the display of magnitudes such as voltages, speeds, times, etc.
The apparatus according to the invention comprises a liquid crystal film band inserted between a first conducting electrode and a second resistive electrode. A first power supply is connected between the electrodes and a second power supply is connected between the two end of the resistive electrode.
In such an apparatus, the two voltages applied cooperate in the excitation of the liquid crystal which generally has a diffused state over part of the band and a transparent state over the rest of the band. Depending on the particular case in question, it is possible to obtain either a band divided into two parts, having different optical states separated by a boundary or a band of a first optical state having a portion with a second optical state. The length of the diffused part in the first state and the position and width of the portion in the second state are a function of the values of the two voltages applied and thus constitute an analog representation of one of the voltages when the other is fixed.
In connection with such apparatuses, reference can be made to the article by R. A. Soref entitled "Electronically Scanned Analog Liquid Crystal Displays", published in the Journal "Applied Optics" in June 1970, Volume 9, No. 6, page 1323.
Such apparatus give satisfaction in a certain number of applications. However, they have the disadvantages of introducing a wide unsharp zone at the boundary between the diffused part and the transparent part.